Where can you find reliable climate data if you want to cross check a claim you hear on the news? Harris County Meteorologist Jeff Lindner referred me to two sites recently: The U.S. Drought Monitor and the Southern Climate Impacts Planning Program (SCIPP) website. To help produce these resources, NOAA has collaborated with universities and state climate offices around the country. They make invaluable, data-driven resources for fact checking, research and public-policy planners.
Is It This Hot Everywhere?
It feels as though the lead story on the evening news every night for last two months has been the extreme heat in Phoenix. Simultaneously, the Houston area has experienced extreme heat and humidity, and the resurgence of drought conditions. The news stories inevitably tie any departure from “normal” to “climate change” and blame it on the burning of fossil fuels – usually without citing the source of their information.
So, imagine my surprise when I explored the U.S. Drought Monitor for the week of 7/25/23 and discovered that areas to the north and east of Texas were wetter and cooler than normal. “Record-setting rains were recorded over western Kentucky and the area had significant flooding,” they said. And “Temperatures were cooler than normal over most of the central Plains, Midwest and Mid-Atlantic with departures of 2-4 degrees below normal widespread.”
Climate Is an Average of Cycles
While still at U.S. Drought Monitor, I looked up Texas droughts since 2000.
Note the gaps between droughts. Also note how the relatively light gap from 2015 to 2019 corresponds to the Tax Day, Memorial Day, Harvey and Imelda floods we had during that period.
The graph below measures departures from average annual precipitation for the upper Texas Coast. This graph goes back to 1895. So to compare it to the one above, focus on the far right. Notice the big dip (brown area) around 2010, then the green peak that corresponds to the flood years.
Note how the largest brown area corresponds to the Dust Bowl years of the 1930s. But also note how peaks follow valleys in cycles.
While still on the SCIPP web site, I found another drought tool that lets you look up precipitation by date over various time periods. It’s still not fully functional yet. So far, they only have data for Louisiana. But when I looked up data for July 23-29, it compared the same week going back to 1900. The numbers below are less important than the dates associated with them in the last two columns.
Note how virtually all of the wettest and driest weeks on record occurred more than 90 years ago, before the rise of the internal combustion engine.
Also note that some of the wettest weeks on record for Louisiana occurred during those Dust Bowl years; Louisiana was not part of the Dust Bowl geographically.
Elsewhere on the SCIPP site, I found pages and tools that let you compare rainfall and temperature by year and month. Here’s where we are so far for 2023.
But look at 2017, the year of Hurricane Harvey. They needed to establish a totally new vertical scale for rainfall!
The last SCIPP chart that I’ll discuss shows the average temperatures; daily highs/lows; minimums and maximums for any given reporting station.
SCIPP has dozens of other useful tools for students, fact checkers, and weather bugs to explore.
What Causes Drought/Flood Cycles?
Various factors influence drought/flood cycles. They include climatic, environmental, and geological elements. Cycles are often region-specific and caused by multiple factors. According to ChatGPT, primary causes include:
- Climate variations, such as El Niño and La Niña
- Ocean currents and temperatures
- Atmospheric circulation patterns
- Topography and geography, such as mountains, proximity to large bodies of water, etc.
- Land use and vegetation changes, such as deforestation, urbanization, and agricultural practices (a major factor in the Dust Bowl years).
- Natural disasters, such as hurricanes
- Rainfall variability. Even absent climatic changes, certain regions naturally experience periods of higher or lower rainfall.
- Climate change, caused not just by emissions but the shape of the Earth’s orbit and wobble in the Earth’s axis.
Specific causes and interactions of these factors can vary from region to region.
Beware of generalizations about climate change based on individual events, short time periods, and isolated locations.
Climate Disasters in Historical Context
Understanding these complexities is essential for better preparedness and mitigation strategies to minimize the impacts of such natural cycles.
Climate disasters have existed for thousands of years. Go to the Four Corners area and visit Chaco Canyon, Canyon de Chelly or Mesa Verde. A prolonged drought contributed to wiping out the Anasazi culture a thousand years ago.
Likewise, the Texas shoreline has been advancing and retreating for millions of years. Sea levels can rise or fall more than a hundred meters between glacial periods.
“Glacial periods last tens of thousands of years. Temperatures are much colder, and ice covers more of the planet. On the other hand, interglacial periods last only a few thousand years and the climate conditions are similar to those on Earth today. We are in an interglacial period right now,” according to the American Museum of Natural History.
Sea levels can rise or fall more than a hundred meters between glacial cycles, which have existed for billions of years.
So when you hear the relentless drumbeat of “climate change” every day without data to back it up, now you know how to check whether the reporters did their homework.
Posted by Bob Rehak on 7/31/2023
2062 Days since Hurricane Harvey